Successive pulley drive for drilling machines



Nov. 27, 1928. 11,693,018

w. F. BOCKHOFF SUCCESSIVE PULLEY'DRI'VE FOR DRILLING MACHINES Filed Feb. 26, 1924 2 sneeis-snev 1" -|NVENTOR WITNESS'. I BY x6: Un t 977mm ATTORNEY Nov 27,1928. 1,693,018

W. F. BOCKHOFF SUCCESSIVE PULLEY DRIVE FOR DRILLING MACHINES Filed Feb. 26, 1924 2 Sheets-Sheet 2 I WITNESS INVENTOR ATTORNEY Patented Nov. :27, 1 928- p p UNITED STATES ,WII'LLIAM r. BOCKHOFF, on RICHMOND,

INDIANA, ASSIGNOE TO THE NATIONAL AUTOMATIC TOOL COMPANY, OF RICHMOND, INDIANA, A CORPORATION OF IN- DIANA.

I SUGGESSIVEPULLEY DRIVE FOB DRELLING MAOl-IINES.

Application filed February 26, 1924. Serial No 695,250.

This invention'relat-es to power transmitting mechanisms and is applicable particularly to machine tools such as drilling machines provided with. a plurality of independent trains of mechanism each of which receives power from a common actuator. I

Drilling machines, as commonly constructed, are'provided with a drill-spindle rotating mechanism and a spindle feeding mechanism, of jwhich the'former is suitably connected withtheactuatoi: to rotate the drills, while the latter is adaptedto effect a relativefeeding movement between the drill and the worksupporting table, to cause the drill to be fed into the work. 7

It is to be understood that, as normally actuated, the ratio, between the spindle rotating mechanism and the feeding mechanism is such that maximum efficiency is obtained under normal working conditions.

Heretofore,- power has "been transmitted to these-two mechanismssbyseparate connections with a motor, power shaft or other common' actuator. "Usually the drill-spindle r0- tating mechanism was connected with the actuator by' a suitable belt while the feeding mechanism was positively driventherefrom bv gear-mechanism. With this construction the feed of the drill was positive while its rotation was ,impositive;

Considerable diificulty'has heretofore been experienced in the operation ofdrilling'machines so constructed due to slippage ,of-the spindle-rotating belt when the machine was operating under a heavy load. This slippage causeda reductionin the speed or rotation of thespindles' and the drills carried thereby'while the feed, being geared direct to the actuator, continued at its predetermined speed, .with the result that thedrill was fedinothe workfaster than it could remove themetal, whereby a severe strainwas thrownupon' the feeding-mechanism and the machine column and the'drills were occasionally broken and theywork impaired.

This invention has for an object to provide a power transmitting device-wherein a plurality of interconnectedtrains of mechanism are actuated from a common. actuator and in which the failure of one of the trains will efiect the action ofanother train.

More specifically, this invention .has for an object to provide. a drilling machine with "a power transmitting mechanism including aconimon actuator "and spindle'feeding and rotating devicesactuated thereby, so constructed and arranged that any slippage in the spindlerotating device will cause a slowing down in the speed of the feed.

Other objects and advantages will be in part indicated in the following description and in part rendered apparent therefrom in connection with'the annexed drawings.

To enable others skilled in the art so fully to apprehend the underlying features hereof that they may embody the same'in the various ways contemplated by this invention, drawings depicting a preferred typical construction have been annexed as a part of this disclosure and, in such'drawings, like charactors of reference denote corresponding parts throughout allthe views, of which:

Fig. 1 a side elevation-of a drilling machine embodying the present invention and Fig. 2 is an enlarged detail sectional view showing more clearly the connection between the common actuator and the spindle rotating and feeding mechanisms.

,Referring moreparticularly to the drawings the invention is shown embodied in a conventional form of'drilling machine comprising a baselsupporting a standard 2 upon which is mounted for verticalbodily movement, a drill-spindle head 3, within which is adj ustab'ly secured drill-spindles as 4- (of which only one is shown) fitted with drills as cl. I

A work-table 5 is also mounted for vertical adj ustnient on the standard 2 beneath the head 3 and adapted to hold the work to be operatcd on by the drills cl. v

a As before "stated, the drill spindles are rotated and the head 3 is moved vertically on the standard by a common actuator, and this invention deals with themeans for transknitting powerfrom the actuator to the mechanismsfor effecting therotation of the spindles and the feed of the drills into the work,

In accordance with this invention, the spindles are rotated and the drills are fed into the work by power supplied by a common actuator, preferably an electric motor A which-, -through suitable connections later to be described, rotates a primary pulley 6. Within the upper end of the standard 2 is journaled ashorizontal shaft 7 connected by gears not shown) to a verticalshaft'ifi which, throughsuitable means common to machines of this type, rotates the drill spindles andthe drills carried thereby, Upon. one end of the shaft 7 there is secured a pulley 9 connected by means of a belt 10, with the primary pulley 6.

The head 3 is moved vertically on the standard, to cause the drills (Z to enter and emerge from the work, by a suitable power feed indicated generally as Inasmuch as the feeding mechanism and the spindle rotating mechanism are common stood, detailed illustration and description thereof is deemed unnecessary.

The means for rotating the pulley 7 from v the actuator A preferably comprises a pinion 11 secured to the n'lotor-shaft, which pinion meshes with a gear 12 non-translatably jourv naled on a shaft 13 fixed in bearings 14 carried by the machine base. The gear 12 is provided with a hub 15 to which the pulley 7 is secured by set screws, as 16.

Loosely journaled upon the shaft 13, coaxial with the pulley 6, and of like diameter,

I is a relatively narrow feed actuating pulley 17 supporting a pinion 18 which forms a part of the feeding mechanism It will be observed that the combined widths of the pulleys (i and 17 are substantially the same as the pulley 9 and therefore, due to the increased width of the pulley 9, the friction between the belt 10 and pulley 9 is greater than between the belt and the pulley 6 and therefore any slippage between the motor and the spindle-i."otating mechanism will take place around the pulley 6.

Further as the pulley 17 is connected with the actuator only through the belt 10 any slippage of the belt on the pulley 6 which would slow down the rotation. of the spindles will likewise effect a reduction in the speed of the feeding mechanism.

The belt 10 virtually comprises two independent belts jointed together along the vertical. plane between the pulleys 6 and 17 and is, in effect, two distinct belts one connecting the pulley 6 with the pulley 7 and the other connecting the pulley 7 with the pulley 17; and it is to be understood that this inven tion contemplates the use of such a double belt connection.

This arrangement prevents overloading the machine through excessive feeds caused by a slowing down of the spindle driving mechanisn'l.

From the foregoing description, it will be apparent that there has been provided a power transn iitting mechanism for effecting the rotation and feed of drill-spindles from a common actuator, and in which the feeding mechanism is affected by any failure of the spindle rotating mechanism.

Without further analysis, the foregoing will so fully reveal the gist of this invention that others can, by applying current knowledge, readily adapt itfor various utilizations by retaining" one or more of the .featuresthat,

to machines of this type and are well underfrom the standpoint of the prior art, fairly constituteessential characteristics of either the generic or specific aspects of this invention, and, therefore, such adaptations should be, and are intended to be, comprehended within the meaning and range of equivalency of the following claims. 7

Having thus revealed this invention, I claim as new and desire to secure the follow ing combinations and elements, or equiva lents thereof, by Letters Patent of the United States: p

1. Apparatus of the class described, comprising a work-support, a tool-carrier, means to cause relative feeding movement of said. work-support and tool-carrier, means to impart to said tool-carrier an operative-movement in predetermined ratio with saidrelative feeding movement, and means to compensate for casual adventitious variations in said ratio, said means including co-aXial 'driv ing and driven pulleys of unequal widths, a belt driven by one of said pulleys and driving the other of said pulleys; and independent trains of mechanism driven respectively by the belt and said last named pulley.

2. A power-transmitting mechanism comprising driving and driven pulleys of substantially equal diameter and arranged coaxially in proximity, and a belt arranged to run in constantly predetermined unequal bridged relation upon the joint periphery of said pulleys, said pulleys being capable of relative rotation, whereby, if one of said pulleys be retarded, another of said pulleys may rotate with saidbelt, the latter slipping upon said retarded pulley. v

3. A multiple-spindle drill, comprising a worlcsupport, a plurality of drill-spindles,

means to rotate said spindles, means to feed.

said spindles toward said work-support, and means to compensate for casual variation in the predetermined ratio between the operative speed of said. spindles and saidfeeding movement, said means including a plurality of coaxially arranged pulleys; an operative connection between one of said pulleys and said spindle rotating means; and an operative connection between another of said pulleys and said spindle feed, said first named operative connection including abelt bridging the joint peripheries of said pulleys and having a constant unequal contact with said pulleys.

4. A power-transmitting mechanism com bining a "driving pulley, a belt driven thereby, said belt overhanging one edge of said pulley, a second pulley, remote from said driving pulley, driven by saidbelt, a third pulley, adjacent said first named pulley and co-axial therewith, driven by the overhang ing portion of the belt; and: independent trains of mechanism driven by said second and third pulleys.

5.. A power-transmitting mechanism for drilling-machines comprising a primary driving pulley, a feed driving pulley adjacent and co-axial with said first named pulley and of substantially equal diameter; a beltcircumscribing said pulleys, the width of said belt being substantially the combined width of both of said pulleys; a pulley driven by said belt, the width of said third pulley being equal to the Width of the belt, and independent trains of mechanism driven by said second and third pulleys.

6. A friction drive comprising a driving element; a driven element; a frictional driving connection between said elements, said driving and driven elements being so constructed and arranged that the friction between the driven element and the driving connection is greater than the friction between the driving element and the driving connection, a second driven element coaxial with said driving element also driven by said driving connection, and independent trains of mechanism driven by said driven elements.

7. A power transmitting mechanism combining first and second driven elements; a driver coaxial with said second driven element; a single friction drive for transmitting motion from said driver to said first driven element, said friction drive also being adapted to transmit motion from said driver directly to said second driven element independently of said first driven element; a spindle rotating mechanism actuated by said first driven element; and a spindle feeding mechanism actuated by said second driven element.

8. A friction drive comprising a primemover; two independent trains of mechanism actuated thereby, said trains being connected to a single element to give to said element two distinct movements; frictional connections between said prime-mover and said mechanisms including a driving member common to both mechanisms, and friction means independently connecting said member with first and second driven elements each specific to one of said trains, the friction between said driving member and said connecting means being greater than the friction between the connecting means and the first driven member and less than the friction between the said connecting means and the second driven member, one of said driven members being mounted co-aXial with said driving member.

In witness whereof, I hereunto subscribe my name.

WILLIAM F. BOCKHOFF. 

